Methane (CH4) is a powerful greenhouse gas and plays a key part in global atmospheric chemistry. Natural geological emissions (fossil methane vented naturally from marine and terrestrial seeps and mud volcanoes) are thought to contribute around 52 teragrams of methane per year to the global methane source, about 10 per cent of the total, but both bottom-up methods (measuring emissions)1 and top-down approaches (measuring atmospheric mole fractions and isotopes)2 for constraining these geological emissions have been associated with large uncertainties.

This report provides a summary of the Raising Risk Awareness project’s results and learning. In summarising both the project’s activities and stakeholders’ responses, this report may prove useful to scientists, development agencies and civil society-based organisations who wish to build on this foundational work in the future.

Anthropogenic climate change is expected to strengthen the vertical wind shears at aircraft cruising altitudes within the atmospheric jet streams. Such a strengthening would increase the prevalence of the shear instabilities that generate clear-air turbulence. Climate modelling studies have indicated that the amount of moderate-or-greater clear-air turbulence on transatlantic flight routes in winter will increase significantly in future as the climate changes.

This policy brief concludes that, from the climate science perspective, results show the 2016-17 drought is less severe than the 2010-11 drought in Lamu, while in Marsabit they are comparable. In general, the return time of the event over the regions analysed was low, meaning that this kind of drought is a relatively common event.

This Interim Report on Climate Change over India prepared by the Centre for Climate Change Research (CCCR) in the Indian Institute of Tropical Meteorology (IITM) Pune, is intended to provide a brief overview of (a) Updated assessment of observed climate change over India (b) Future climate projections over India (c) Development of the IITM Earth

Discriminating the climate impacts of half-degree warming increments is high on the post-Paris science agenda. Here the researchers argue that evidence from the observational record provides useful guidance for such assessments.

The average temperature in the United States has risen rapidly and drastically since 1980, and recent decades have been the warmest of the past 1,500 years, according to a sweeping federal climate change report awaiting approval by the Trump administration.

The dramatic warming of the Arctic over the last three decades has reduced both the thickness and extent of sea ice, opening opportunities for business in diverse sectors and increasing human exposure to meteorological hazards in the Arctic. It has been suggested that these changes in environmental conditions have led to an increase in extreme cyclones in the region, therefore increasing this hazard.

Rising global temperatures are causing increases in the frequency and severity of extreme climatic events, such as floods, droughts, and heat waves. We analyze changes in summer temperatures, the frequency, severity, and duration of heat waves, and heat-related mortality in India between 1960 and 2009 using data from the India Meteorological Department. Mean temperatures across India have risen by more than 0.5°C over this period, with statistically significant increases in heat waves.

In April 2016, southeast Asia experienced surface air temperatures (SATs) that surpassed national records, exacerbated energy consumption, disrupted agriculture and caused severe human discomfort. Here we show using observations and an ensemble of global warming simulations the combined impact of the El Niño/Southern Oscillation (ENSO) phenomenon and long-term warming on regional SAT extremes. We find a robust relationship between ENSO and southeast Asian SATs wherein virtually all April extremes occur during El Niño years.

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